Cambridge Analytica is closing down, but the political world it helped create lives on. And one of the worst applications of its technology — the data-driven effort to discourage people from voting, rather than pushing them to the polls — is likely to be an even more important part of Donald Trump’s reelection strategy in 2020. Democrats will need to up their digital game if they plan on beating him.

As the digital organizing director for Hillary Clinton in 2016, I saw firsthand how the effort to reduce voter turnout worked. Weeks before Election Day, a senior official from the Trump campaign told Bloomberg News that “we have three major voter suppression operations under way,” aimed at three groups of voters that were crucial to Clinton: African Americans, young women, and idealistic white liberals.

Cambridge Analytica was crucial to those operations, which targeted each group with negative advertising designed to discourage them from voting. The result: Democratic turnout in highly contested states like Michigan, Wisconsin, and Ohio dropped relative to Obama's election in 2012. It didn’t drop by much — 12,000 votes in Michigan, 27,000 votes in Wisconsin — but it was enough to tip close races and the electoral college.

One clear sign of what to expect in 2020 is that the entire Trump campaign will be run by Brad Parscale, who led the 2016 digital effort that embraced Cambridge Analytica. His promotion suggests Trump will double down on the 2016 digital strategy, and is likely already looking for someone to fill Cambridge Analytica’s shoes.

Those Facebook ads targeting likely Clinton voters in 2016 joined a broader, multi-decade effort by Republicans to keep the Democratic base away from the polls. The right-wing media has promulgated myths of widespread voter fraud, and Republican lawmakers eagerly embraced those myths and introduced more stringent rules on who can vote — rules that made it harder for people of color and those who are low-income to vote. The Trump campaign added a digital dimension to this effort.

What Team Trump did went well beyond the kind of negative advertising that is a standard part of most political campaigns. But there's a strategic and ethical jump between highlighting the negative aspects of your opponent and the anything-goes digital campaign to discourage people from voting that we saw in 2016. That new digital strategy, aided by the disgraced Cambridge Analytica, has convinced me that Trump’s win didn’t come because his campaign expanded the Republican voter base: It came because they depressed Clinton’s.

Microtargeting in politics is neither new nor sinister by nature, and has been standard practice in Democratic political campaigns since we pioneered it with Obama in 2008. But at the core of the Obama campaign, microtargeting and social media was never used to push people away from the polls — it was used to connect people locally, all with the goal of getting their friends to vote. Data was used to share our positive message of hope, and phone calls and door-knocking encouraged people to turn out on Election Day.

That strategy has very little in common with what was done by the Trump team and their digital helpers. Last year, when I appeared on a panel with a Cambridge Analytica representative, I was horrified to hear their explanation of the Trump microtargeting strategy, including a sophisticated secret weapon they deployed that characterized portions of the American public as “deadbeats.”

In 2016, we underestimated the scale of this effort to reduce voter participation. Democrats certainly raised the alarm regarding online abuse and Russian hacking. But we did not connect the dots. We also did not spend enough on digital advertising, especially on content to reach communities of color. I ran digital outreach to encourage people of color to vote, and while we invested, it was insufficient. Overall, the Trump campaign outspent Clinton’s on digital versus television, and the strategy worked.

Democrats have little chance of bringing about the rumored “blue wave” this year — the first, vital step in preserving our democracy — without fighting fire with fire and upping our own digital game. We should not shy away from bold messages that explicitly appeal to people of color and counteract the hateful messages of the Trump campaign. This means supporting organic content creators, and allowing their messages to get picked up and remixed, mirroring successful social movements like #MarchForOurLives or #BlackLivesMatter.

Instead of fully controlling the message, Democrats should be ready to amplify what is happening on the ground. That includes figuring out how to utilize the “anecdata” learned from the field — the stories we hear from supporters and organizers that, if repeated in different locations, can be indicators of how our message or tactics are being perceived.

Democrats should also revisit the playbook that made us digital mavens in the first place: grassroots organizing and authentic, scaled, person-to-person communication rooted in relationships. Until 2016, Democrats were acknowledged to be the leaders in investing in grassroots campaigns. We can't walk away from that, but must invest even more in a strong ground game. It might have made the difference in 2016.

That game wasn’t just aided by Cambridge Analytica. Trump supporters used a playbook pioneered by the left, using private Facebook groups to build community, organically created Twitter personalities to coordinate in private direct message groups, and raw, unbranded content that spread the message. But because so much of this was cribbed from Democrats, this can also be easily counteracted. On-the-ground voter turnout efforts almost always benefit Democrats, as we’ve recently seen in Pennsylvania, West Virginia, and Alabama. We just have to make the effort.

Venerable Democratic institutions have experience fighting voter suppression in the courts and at the polls. Cambridge Analytica may be gone, but we need a new generation to fight against those who will seek to build on its digital legacy. The peddlers of misinformation, fake news, and targeted deception have the same goals as those exploiting redistricting and voter ID laws, and the battle to defeat them will be just as treacherous. Their work is conducted in secret, aided by old enemies in foreign governments, on platforms our leaders do not understand. But without fighting back, we risk everything.

Jess Morales Rocketto is the political director for the National Domestic Workers Alliance and chair of We Belong Together, the feminist campaign for immigration reform. She was the digital organizing director for Hillary Clinton's 2016 campaign.